This invention pertains to a class of drug inhalers that uses an air jet to first entrain liquid medicine and then nebulize or atomize the liquid by impacting the medicine-laden air jet on a flat surface. This aerosol is then inhaled by the patient.
It is an object of the invention to provide a breath-activated fluidic switch and method for shutting off the medicine when the patient is not inhaling, whether he is exhaling or has removed the drug delivery device from its position of inhaling.
According to the invention, a fluidic switch is provided for a drug inhaler which uses an air jet to first entrain liquid medicine, then nebulize or atomize the liquid by impacting the medicine-laden air jet on a flat surface. A fluidic switch turns on and off the entrainment of liquid medicine. A feature of the invention is that the fluidic control port is not mounted at the traditional position at the exit of the power nozzle but is downstream thereof and preferably by approximately three nozzle widths.